Langsat is
native to Thailand, Malaysia and Indonesia. Although it is planted
sporadically throughout the tropics, commercial production is mostly in Thailand, Malaysia,
Indonesia, the Philippines, and Vietnam.

Botanical Synonyms

Aglaia dookoo, Aglaia domestica, and Aglaia aquea.

Description

Langsat is
a medium to large tree, cultivated trees usually 15-30 feet (5-10 m) tall, while
seedling trees can reach 90 feet (27 m) or more in height. The trunk is
generally straight and the branched relatively open. The leaves are
alternate and compound, around 9-20 inches (23-51 cm) long, with 5-7 leaflets.
The perfect flowers are small and white, and borne on cauliflorous spikes 4-12
inches (10-31 cm) long that emerge from older branches. Fruits are spheroid,
ellipsoid, or ovoid, around 1-2 inches (2.5-5 cm) in diameter, and occur in clusters
of 4-40. The yellowish peel is easily removed to reveal whitish
translucent, aromatic, juicy pulp divided into 5-6 segments. The flavor is
reminiscent of sweet grapefruit. Fruits usually contain 1-3 greenish
seeds.

Propagation and Culture

Langsat may be propagated by
seeds, cuttings, airlayers or grafting. Seeds must be planted fresh, as
they lose viability rapidly if allowed to dry out. Germination occurs in
2-3 weeks, and the seedlings are slow growing. Trees may be grafted at
about 1 year of age, or when the trunk is about the diameter of a pencil.
They can be grafted by cleft, side veneer, bud, or approach.

Young trees should have 50%
shade for the first 2-3 years. Langsat trees prefer moist, fertile soil
and high relative humidity for best growth. Since they are slow growing,
they are often interplanted with other fruit trees. They require tropical
conditions, and will grow from sea level to 2,400 feet (732 m) elevation.
Seedling trees may take 10-30 years or more to fruit, while grafts or airlayers
can fruit in 5-6 years with good care. A mature tree can produce from
90-650 pounds (41-308 kg) of fruit per year. In Puerto Rico, langsat fruits from
August to October.

Cultivars and Related Species

Lansium domesticum is a highly variable species,
with different forms that have been classified by some taxonomists as distinct
species. There are five basic varieties, but there may be intermediate
forms with overlapping characteristics:Langsat - Slender tree with open crown, fruits in clusters of 6-40.
Ovoid fruit about 1 inch (2.5 cm) in diameter, thin peel containing latex, sour
to sweet. Contains 1-3 green, bitter seeds. Adapted to climates with
distinct seasons. Cultivars include 'Conception' and 'Paete'
(Philippines), 'Uttaradit' (Thailand), and 'LA8' and 'LA9' (Malaysia). 'Casto'
is a selection from Puerto Rico with a large fruit, low latex, and high yields.Duku - A vigorous, spreading, symmetrical tree with dense foliage, fruit
in clusters of 4-12. Fruits are spheroid, 1-2 inches (2.5-5 cm) in diameter,
with a thick peel, little to no latex, and a sweet, aromatic pulp. The
seed is ellipsoid in shape. Adapted to tropical conditions. 'Du 1'
is a Malaysian varietyDuku Langsat - Has characteristics intermediate to langsat and duku.
Fruit in clusters of 5-25, ovoid shape, sweet and aromatic, thick peel.
Varieties include 'DL1' and 'DL2' from Malaysia.Longkong (dokong) - From Thailand, fruit spheroid, about 1.5 inches (4 cm)
in diameter, thick peel with no latex, soft, sweet, aromatic pulp, and seedless
or with very few seeds.Kokosan - From Indonesia, with hairy leaves and compact fruit
clusters. Fruits dark yellow, with sour pulp and large seeds.

There are about 15 species in the genus Lansium.
Lansium membranaceum, from Indonesia, has an edible but sour fruit up
to 1.6 inches (4 cm) long.

Uses

Langsat
fruits are usually eaten fresh, but may be canned in syrup.

Nutritional composition per 100 g langsat fruit

Carbohydrate

7.8-14.2 g

Protein

0.4-0.7 g

Calcium

10-19 mg

Phosphorous

20 mg

Iron

1 mg

Thiamine

0.05 mg

Riboflavin

0.02 mg

Niacin

0.5 mg

Vitamin C

4-13.4 mg

Several
parts of the plant have medicinal uses. The fruit peel is dried and burned
to repel mosquitoes; it is also used to treat intestinal parasites and
diarrhea. Powdered seeds are used to reduce fever, and the bark is used to
treat malaria and scorpion stings.